Removing Ring Door Device

I have 2 Ring2 (backdoor and frontdoor). I bouht a new Ring3+ to replace the frontdoor Ring2 that died. I had it working but somehow cannot add it to the App. I can receive a frontdoor press and can communicate with it from the Notifications but my App only shows the Ring2 (backdoor). I tried numerous times to add the new Ring3+ to the App but was unable - I was going in circles/crazy. I decided to start from scratch - removing/re-installing the App and re-adding the backdoor and frontdoor. I managed to re-add the Ring2 (backdoor) but cannot add the frontdoor Ring3+. It says that the owner has to release the device. Now I am in a real circle: I cannot add the device because it is owned. I cannot remove the device because it is not in my list in the App. Also...why do we need a battery in the Ring3+ when it has AC!!!! REALLY..REALLY crazy/inconvenient/troublesome!!!! ...having to re-charge the battery even when it has AC connected to it! Lee